题干

把下列各数填在相应的大括号里.
﹣2,0.50,3
1
5
,432,20,0,﹣
1
3
,0.789,﹣2016,3
整数集合{                                          …}
负整数集合{                                        …}
正分数集合{                                       …}
负分数集合{                                       …}.
上一题 下一题 0.0难度 选择题 更新时间:2018-01-08 10:36:50

答案(点此获取答案解析)

解:整数集合{﹣2,432,20,0,﹣2016,3}
负整数集合{﹣2,﹣2016}
正分数集合{0.50,3
1
5
,0.789}
负分数集合{﹣13<

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                                                                                                  泥 泞
                                                                                                  迟子建
      ①北方的初春是肮脏的,这肮脏当然缘自于我们曾经热烈赞美过的纯洁无瑕的雪。在北方漫长的冬季里,寒冷催生了一场又一场的雪,它们自天庭伸开美丽的触角,纤柔地飘落到大地上,使整个北方沉沦于一个冰清玉洁的世界中。如果你在飞雪中行进在街头,看着枝条濡着雪绒的树,看着教堂屋顶的白雪,看着银色的无限延伸着的道路,你的内心便会洋溢着一股激情:为着那无与伦比的壮丽或者是苍凉。
      ②然而春风来了。春风使积雪融化,它们在消融的过程中容颜苍老、憔悴,仿佛一个即将撒手人寰的老妇人。雪在这时候将它的两重性毫无保留地暴露出来:它的美丽依附于寒冷,因而它是一种静止的美、脆弱的美;当寒冷已经成为西天的落霞,和风丽日映照它们时,它的丑陋才无奈地呈现。
      ③纯美之极的事物是没有的,因而我还是热爱雪。爱它的美丽、单纯,也爱它的脆弱和被迫的消失。当然,更热爱它们消融时给这大地制造的空前的泥泞。
      ④小巷里泥水遍布;排水沟因为融雪后污水的加入而增大流量,“哗哗”地响;燕子在潮湿的空气里衔着湿泥在檐下筑巢;鸡、鸭、鹅、狗将它们游荡小巷的爪印带回主人家的小院,使院子里印满无数爪形的泥印章,宛如月下松树庞大的投影;老人在走路时不小心失了手杖,那手杖被拾起时就成了泥手杖;孩子在小巷奔跑嬉闹时不慎将嘴里含着的糖掉到泥水中了,他便失神地望着那泥水“呜呜”地哭,而窥视到这一幕的孩子的母亲却快意地笑起来……
      ⑤这是我童年时常常经历的情景,它的背景是北方的一个小山村,时间当然是泥泞不堪的早春时光了。
      ⑥我热爱这种浑然天成的泥泞。
      ⑦泥泞常常使我联想到俄罗斯这个伟大的民族,罗蒙诺索夫、柴可夫斯基、陀思妥耶夫斯基、托尔斯泰、蒲宁、普希金就是踏着泥泞一步步朝我们走来的。俄罗斯的艺术洋溢着一股高贵、博大、阴郁、不屈不挠的精神气息,不能不说与这种春日的泥泞有关。泥泞诞生了跋涉者,它给忍辱负重者以光明和力量,给苦难者以和平和勇气。一个伟大的民族需要泥泞的磨砺和锻炼,它会使人的脊梁永远不弯,使人在艰难的跋涉中懂得土地的可爱、博大和不可丧失,懂得祖国之于人的真正含义。当我们爱脚下的泥泞时,说明我们已经拥抱了一种精神。
      ⑧如今在北方的城市所感受到的泥泞已经不像童年时那么深重了。但是在融雪的时节,我走在农贸市场的土路上,仍然能遭遇那种久违的泥泞。泥泞中的废纸、草屑、烂菜叶、鱼的内脏等等杂物若隐若现着,一股腐烂的气味扑入鼻息。这感觉当然比不得在永远有绿地环绕的西子湖畔撑一把伞在烟雨淳淳中耽于幻想来得惬意,但它仍然能使我陷入另一种怀想,想起木轮车沉重地碾过它时所溅起的泥珠,想起北方的人民跋涉其中的艰难的背影,想起我们曾有过的苦难和屈辱,我为双脚仍然能触摸到它而感到欣慰。
      ⑨我们不会永远回头重温历史,我们也不会刻意制造一种泥泞让它出现在未来的道路上,但是,当我们在被细雨洗刷过的青石板路上走倦了,当我们面对着无边的落叶茫然不知所措时,当我们的笔面对白纸不再有激情而苍白无力时,我们是否渴望着在泥泞中跋涉一回呢?为此,我们真应该感谢雪,它诞生了寂静、单纯、一览无余的美,也诞生了肮脏、使人警醒给人力量的泥泞。因此它是举世无双的。

同类题4

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    Are you using a dating App to make friends? How do you know that Ben from London is really 25-year-old? Is his photo taken recently? Is his name even Ben? Dating apps can be tricky to operate, particularly when you're trying to know whether someone is trustworthy, but one thing you can't cheat is your gene, which is why a new dating app is using DNA as a basis for its match.

    A dating app named Pheramor requires all users to hand in a cheek sample, from which a team of in-house scientists using a specially-created tool can queue the specific genes connected with attraction and then identify which users might be suitable. The process works by separating the 11 genes that link to our pheromones(信息素), the chemical signals that are believed to control one's attraction. Combining this data with the personal information allows the app to make very specific matches.

    “Pheramor uses both your biology and your social technology: we collect your genetic data through a cheek sample and collect your like, dislikes, and interest from your social media introductions like Facebook, Twitter, etc,” the app's website explains. “All of them will be used in our specific software, which is designed to learn what you prefer.”

    The co-founder Brittany Barreto, who has a PHD in genetics added that Pheramor's technology digs deeper than traditional dating apps, making it almost impossible for people to cheat their way to a date.

    The Houston-based app is already up and running but hopes to be officially put into market in February with 3,000 members.